| Objective: To explore the effect of Vacuum Sealing Drainage(VSD)technique in improving the Postoperative survival rate of narrow pedicled skin flap,and provide guidance for clinical application.To observe the effect of 3 methods on the survival area of narrow pedicled flap,which are local injection of Stromal Vascular Fraction(SVF),external VSD device in a forward direction and the combination of these two,and preliminarily explore the mechanism of promoting the survival of narrow pedicled flaps.To observe influence on the survival area of the narrow pedicled flap after congestion,which was treated by VSD combined with SVF at different time points,so as to provide guidance for the treatment opportunity of necrosis of the flap after clinical operation.Methods: 1.30 SD rats were randomly divided into three groups of 10 each.One side was randomly selected to make the model of narrow pedicled flap.The width-length ratio of the pedicle was 0.8cm: 2cm,and the distal end carried a circular flap with a diameter of 3.5cm.The pedicle was about 1cm from the midline of the back.According to the different drainage directions of the VSD,it was divided into the VSD in a forward direction group(group A),that is,the drainage direction was from the pedicle to the flap;the VSD in a backward direction group(group B),the direction of drainage was from the flap to the pedicle;no VSD control group(group C).VSD was used continuously for five days after the operation to observe the appearance of the flap.The perfusion velocity of the flap was monitored 4 hours after the operation.The flap specimens were collected immediately,1,3,5 and 7 days after the operation.The expression of CD34 in the flap tissue was detected by immunohistochemistry.The pathological changes of the flap were observed by HE staining.The MVD value and percentage of flap survival area were calculated.2.40 SD rats were randomly divided into four groups of 10 each.One side was randomly selected to make the model of narrow pedicled flap.According to the application of VSD and SVF,they were divided into experimental group I(group I): local injection of a certain amount of SVF combined with VSD in a forward direction;Experimental group 2(Ⅱ group): local injections of SVF;Group three(Ⅲ group): local injections of the same amount of PBS combined with VSD in a forward direction;Group four(Ⅳ group): the flap local injections of amount of PBS group.Postoperative VSD was used continuously for five days to observe the appearance of the flap.The flap samples were collected immediately,1,3,5 and 7 days after the operation.The expressions and contents of CD34,VEGF and IL-6 in the flap were detected by immunohistochemistry and ELISA,and the MVD value and percentage of flap survival area were calculated.3.50 SD rats were randomly divided into five groups of 10 each.One side was randomly selected to make a model of narrow pedicled flap.According to the different application time of VSD combined with SVF after the operation,it can be divided into: Immediately after blood stasis(group a),24 h after blood stasis(group b),2 days after blood stasis(group c),3 days after blood stasis(group d),4 days after blood stasis(group e).VSD was used continuously for five days to observe the appearance of the flap.The skin flap samples were collected immediately,1 day,3 days,5 days,7 days and 11 days after surgery.The expressions and contents of CD34,VEGF and IL-6 in the skin flap tissues at different time points were detected by immunohistochemical and ELISA methods,and the MVD value and percentage of flap survival area were calculated.Results: 1.Percentage of flap survival area in group A and group B on the 7th day after operation was higher than that in group C,and that in group A was higher than that in group B(P<0.05).The perfusion velocity of blood flow of the flap was detected 4 hours after the operation,and it was faster in group A than in group B than in group C(P<0.05).The pathological examination of HE staining showed that the microthrombus and tissue injury at each time point after the operation in group A and group B were lighter than those in group C,and the latter was lighter than those in group B.The expression of CD34 was detected by immunohistochemistry at each time point after operation,and the CD34 expression gradually increased in the same group of flaps,and then gradually decreased after reaching a certain peak value.Compared with different groups at the same time point,group A was higher than group B and higher than group C,and the peak appeared earlier in group A and group B.The MVD value of the three groups of skin flaps increased gradually after operation,which was higher in group A than group B than group C(P<0.05).2.The survival rate of skin flap in group Ⅰ,group,Ⅱ,groupⅢ,Ⅳ on the 7th day decreased successively in the four groups(P < 0.05).The content of VEGF,CD34 and IL-6 of flap after operation were of a similar change trend,which increased after surgery and gradually declined after the peak.The peak ofⅠ,Ⅱ group,Ⅲ were earlier than Ⅳ group.At the same time point,the content of VEGF and CD34 decreased successively in the four groups(P<0.05).IL-6 in the flap and group Ⅰ is lower than the other three groups,group Ⅱ,Ⅲ lower than group Ⅳ,P < 0.05;No significant differences between Ⅱ and Ⅲ group.Four groups of flap surgery MVD value are increased gradually,the same point in time,Ⅰ above Ⅱ group is higher than Ⅲ above Ⅳ group,P < 0.05).3.The survival rate of the flaps was measured and calculated on the 11 th day after the operation in group a,b,c,d and e,and the survival rate of the flaps decreased successively in the a,b,c,and d groups(P<0.05),but in the d and e groups,there was no significant difference in survival area,P>0.05.The expressions and contents of VEGF,CD34 and IL-6 in the five groups of skin flaps showed similar trends after the operation,which gradually increased after the operation and then decreased after reaching the peak value.After treatment,the content of VEGF and CD34 decreased successively in the five groups(P<0.05).The content of IL-6 in the flap increased successively,P<0.05.There was no significant difference between groups before treatment.The MVD value of the four groups of skin flaps increased gradually after operation.Compared at the same time point,the value of group a was higher than that of group b,higher than that of group d and higher than that of group e,P<0.05.Conclusion: 1.Different drainage directions of VSD can accelerate the perfusion velocity of blood flow of the narrow pedicled flap,reduce the congestion and edema of the flap,reduce the formation of microthrombus,reduce the tissue pathological injury,promote the flap angiogenesis,improve the blood supply of the flap,improve the survival area of the flap,and the effect of VSD in a forward direction is better.2.Both VSD and SVF can reduce congestion,edema,and promote the secretion of VEGF and CD34,reduce inflammation,promote the vascularization of the flap,and thus promote the survival of the flap,which the combination works better.3.The application of VSD combined with SVF can reduce the necrotic area and improve percentage of flap survival area within a certain period of necrosis after the operation of narrow pedicled flap.The earlier the treatment is started,the better the prognosis will be. |
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